The following article is written by happiness expert and psychologist Dr Melissa Weinberg from Deakin University’s School of Psychology.

If you had planned a trip to London in the past few weeks you may have felt inclined to cancel, following the terror attack on March 22. Khalid Masood, 52, killed five people and injured about 50 others, when he mowed down pedestrians on Westminster Bridge before running into the grounds of the Palace of Westminster armed with knives. For a few days after the event, the emotional intensity was high, and many feared that another terrorist attack might follow.

The natural reaction of wanting to cancel travel plans to a destination that has just experienced a terrorist attack can be explained through the concept of ‘availability bias’.

Availability bias causes us to overestimate the frequency of attacks in general, because this latest attack is still fresh in our mind. The irony of this, of course, is that the reason we’re affected by it is partly because it’s unusual, but that has the reverse effect of making us believe it is more common than it actually is.

'Availability bias causes us to overestimate the frequency of attacks in general, because this latest attack is still fresh in our mind.'

Dr Melissa Weinberg,School of Psychology, Deakin University

How our brain plays tricks on us

To demonstrate availability bias – if I take a random word from all the words in this article, is it more likely that the word starts with the letter ‘k’, or that ‘k’ is the third letter of the word?

Automatically, most people will start to think of examples of words that fit either category. Because we store words alphabetically according to their first letter, it’s much easier to think of words that start with the letter ‘k’ – king, kite, kick, koala – and much harder to think of words that have ‘k’ as their third letter.

But you only have to look back at the first sentence of this section to see that instances of ‘k’ being the third letter of the word are, in fact, far more frequent.

This ‘error’ captures what is known in psychology, economics, and now many other fields as the ‘availability bias’, thanks largely to the work of two eminent researchers, Daniel Kahneman and Amos Tversky.

The availability bias explains how we tend to misconstrue the frequency of an event by the ease with which we can recall it. It’s why people tend to be more scared of flying in a plane than driving in a car, and why we become very concerned about a particular cause or charity when the media tell us heart-wrenching stories of people who have suffered.

Instances become more ‘available’ to your mind the more recent, unusual, and emotionally charged they are. Of course, the media know this, and often use it to their advantage. That’s why we often see media campaigns portraying emotionally-charged stories to raise awareness. The logic: the more emotionally-intense the material – the more ‘available’ it is in your mind – the more important you think it is – the more you will be drawn to take action.

Basically, your brain is taking a shortcut. It’s supposed to help you get to a solution faster, but it doesn’t always get you to the right one. Kahneman and Tversky were pivotal in introducing the world to a range of biases and heuristics, showing how the mistakes that we make are not random, but are in fact, systematic and largely predictable.

Is a terrorist attack likely in Australia in the near future?

The Australian Unity Wellbeing Index has included this question in almost all of its surveys since the project began in 2001. According to the latest survey results from April 2016, the percentage of Australians who believe a terrorist attack is likely in the near future is about 75% – the highest ever recorded, and about 35% higher than the rate recorded in August 2013. For context, Australia’s terrorism alert was raised to ‘high’ in September 2014, which, no doubt, heightened public awareness to threat.

But perhaps more telling, a series of coordinated terror attacks occurred in Belgium in April 2016, just days prior to the latest survey.

And while it could be argued that there is good reason to suspect a terror attack in Australia is more likely now than it was a few years ago, Australians also reported being more satisfied with their personal safety in the latest survey than ever before. The seemingly conflicting findings suggest an availability bias. Despite feeling safe, the available instance of a recent, unusual and emotionally-charged event influenced the belief in the likelihood of a terrorist attack occurring in Australia in the near future.

Can I use this to my advantage?

If we know that our brains make mistakes, but that the mistakes are predictable, we can use this to our advantage when making important decisions. What we essentially need to do is to look for evidence to the contrary – facts and evidence outweigh the availability bias every time.

It doesn’t mean that you shouldn’t donate money to a worthy cause, or that you shouldn’t fear that bad things may happen in the future, but understand that fundamentally, your decisions are not always as rational as you think they are.

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